1 Features
1• 3.3-V, 5-V, 12-V, and Adjustable Output Versions
• Adjustable Version Output Voltage Range: 1.2 V
to 37 V ±4% Maximum Over Line and Load
Conditions
• 3-A Output Current
• Available in 7-Pin TO-220 and TO-263 (Surface-
Mount) Package
• Input Voltage Range Up to 40 V
• 150-kHz Fixed-Frequency Internal Oscillator
• Shutdown and Soft-Start
• Out-of-Regulation Error Flag
• Error Output Delay
• Low Power Standby Mode, IQ, Typically 80 μA
• High Efficiency
• Uses Readily Available Standard Inductors
• Thermal Shutdown and Current-Limit Protection

2 Applications
• Simple High-Efficiency Step-Down (Buck)
Regulator
• Efficient Preregulator for Linear Regulators
• On-Card Switching Regulators
• Positive to Negative Converter

3 Description
The LM2599 series of regulators are monolithic
integrated circuits that provide all the active functions
for a step-down (buck) switching regulator, capable of
driving a 3-A load with excellent line and load
regulation. These devices are available in fixed output
voltages of 3.3 V, 5 V, 12 V, and an adjustable output
version.
The LM2598 is a member of the LM259x family, with
additional supervisory and performance features
added.
Requiring a minimum number of external
components, these regulators are simple to use and
include internal frequency compensation, improved
line and load specifications, fixed-frequency oscillator,
Shutdown and Soft-start, error flag delay, and error
flag output.